Research in my group, the Lightwave Communications Laboratory, is focused on investigating ultrafast optical techniques with application to communication networks and signal processing. My graduate students and I are working on several exciting and innovative research projects, which benefit from close collaborations with government and industrial research laboratories. A few examples of these projects fare given below: Physical (Optical) Layer Network Security: Security in fiber optic networks is becoming of critical importance due to the nature and volume of the data that is transported. The optical layer of a network is itself vulnerable to attack by eavesdropping or jamming. My group is investigating several approaches using optical signal processing to counter these attacks, including optical steganography, all-optical encryption devices, anti-jamming techniques, and survivable network architectures. Optical Code Division Multiple Access (CDMA): Incoherent optical CDMA networks can offer several important system advantages that cannot be achieved with other multiplexing techniques such as TDM and WDM, including asynchronous access, soft blocking, privacy, scalability and variable quality of service. We are developing novel integrated technologies that will enable the realization of practical optical CDMA networks, which will be strong candidates for future broadband access networks. Nonlinear Optical Signal Processing for Ultrafast Networks: Based on nonlinear phenomena in semiconductor devices and nonlinear fibers, numerous optical signal processing functions can be achieved which can enhance the performance of ultrafast optical networks. We are studying novel devices and their applications, including optical thresholding, auto-correlation peak extraction, demultiplexing, physical layer security enhancement, and interferometric noise suppression Optical Cancellation of RF Interference: Wireless communictions systems often suffer from co-site interference, where the signal from a nearby transmission antenna interferes with simultaneously receiving a weak signal in a nearby frequency band. Multipath effects make this problem especially challenging. We are investigating optical and optoelectronic signal processing techniques to process RF signals from single antennas as well as phased arrays, enhancing their performance and enabling rapid reconfigurability. The Photonic Neuron: Using nonlinear optical and photonic materials, we have recently built a hybrid analog/digital signal processing device which performs all the functions of a physiological neuron, but one billion times fast. Our spiking neuron is faster and more efficient than a digital computer, and does not suffer from the noise accumulation of analog electronics. Using the photonic neuron, we are implementing sophisticated, ultrafast signal processing circuits and systems which emulate visual, auditory, and motor functions found in biological organisms. With a high degree of interaction between government and industrial research laboratories, the Lightwave Communications Laboratory offers students an opportunity to be involved in the creation of technology for the next generation of optical signal processing, computing and communications systems. Please visit my lab website to find out more information about my group and our research, as well as to download a booklet containing some of our recent papers. To find out more about my group’s collaborations with industry, you can also visit the website of the Center for Network Science and Applications.
B. J. Shastri*, J. Chang*, A. N. Tait, M. P. Chang, B. Wu, M. A. Nahmias, and P. R. Prucnal, “Ultrafast Optical Techniques for Communication Networks and Signal Processing,” in All-Optical Signal Processing: Data Communication and Storage Applications, S. Wabnitz and B. J. Eggleton (Eds.) Springer Berlin Heidelberg, 2015, ch. 15, pp. 469–503. [*equal contribution].
A. N. Tait, M. A. Nahmias, Y. Tian, B. J. Shastri, and P. R. Prucnal, “Photonic Neuromorphic Signal Processing and Computing,” in Nanophotonic Information Physics, Springer-Verlag Berlin Heidelberg, 2013, ch. 8, 40 pages (in press).
B. Wu, B. J. Shastri, and P. R. Prucnal, “Secure Communication in Fiber-Optic Networks,” in Emerging Trends in Information and Communication Technologies Security, B. Akhgar and H. R. Arabnia, Eds. Waltham, MA: Elsevier (Morgan Kaufmann), 2013, ch. 11, pp. 173–183.
M. A. Nahmias, A. N. Tait, B. J. Shastri, T. Ferreira de Lima, and P. R. Prucnal, “Excitable laser processing network node in hybrid silicon: analysis and simulation,” Optics Express, vol. 23, no. 20, pp. 26800-26813.
B. Wu, B. J. Shastri, P. Mittal, A. N. Tait, P. R. Prucnal, “Optical signal processing and stealth transmission for privacy,” IEEE Journal of Selected Topics in Signal Processing, vol. 9, no. 7, pp. 1185–1194.
M. P. Chang, N. Wang, B. Wu, P. R. Prucnal, “A Simultaneous variable optical weight and delay in a semiconductor optical amplifier for microwave photonics,” IEEE/OSA Journal of Lightwave Technology, vol. 33, no. 10, pp. 2120–2126.
M. P. Chang, C.-L. Lee, and P. R. Prucnal, “Adaptive optical self-interference cancellation using a slow and fast light tunable delay,” IEEE Photonics Technology Letters, vol. 27, no. 9, pp. 1081–1021, May 2015.
A. N. Tait, J. Chang, B. J. Shastri, M. A. Nahmias, and P. R. Prucnal, “Demonstration of WDM weighted addition for principal component analysis,” Optics Express, vol. 23, no. 10, pp. 12758–12765, May 2015.
B. J. Shastri, M. A. Nahmias, A. N. Tait, B. Wu, and P. R. Prucnal, “SIMPEL: Circuit model for photonic spike processing laser neurons,” Optics Express, vol. 23, no. 6, pp. 8029–8044, Mar. 2015; selected/featured in Virtual Journal for Biomedical Optics (VJBO), vol. 10, no. 4, Apr. 2015.
M. A. Nahmias, B. J. Shastri, A. N. Tait, M. Eder, N. Rafidi, Y. Tian, and P. R. Prucnal, “Normalized pulsed energy thresholding in a nonlinear optical loop mirror,” Applied Optics, vol. 54, no. 11, pp. 3218-3224, Apr. 2015.
A. N. Tait, M. A. Nahmias, B. J. Shastri, and P. R. Prucnal “Broadcast and weight: an integrated network for scalable photonic spike processing,” IEEE/OSA Journal of Lightwave Technology, vol. 32, no. 21, pp. 3427–3439, Nov. 2014.
B. Wu, B. J. Shastri, and P. R. Prucnal, “System performance measurement and analysis of optical steganography based on amplifier noise,” IEEE Photonics Technology Letters, vol. 26, no. 19, pp. 1920–1923, Oct. 2014.
J. Chang, J. Meister, P. R. Prucnal, “Implementing a novel highly scalable adaptive photonic beamformer using “blind” guided accelerated random search", IEEE/OSAJournal of Lightwave Technology, vol. 32, no. 20, pp. 3623–3629, Oct. 2014.
B. J. Shastri*, A. N. Tait*, M. A. Nahmias*, and P. R. Prucnal, “Photonic spike processing: ultrafast laser neurons and an integrated photonic network,” IEEE Photonics Society Newsletter, vol. 28, no. 3, Jun. 2014. [*equal contribution]
B. Wu, Z. Wang, B. J. Shastri, M. P. Chang, N. A. Frost, and P. R. Prucnal, “Temporal phase mask encrypted optical steganography carried by amplified spontaneous emission noise,” Optics Express, vol. 22, no. 1, pp. 954–961, Jan. 2014.
J. Chang, M. P. Fok, R. M. Corey, J. Meister, and P. R. Prucnal, "Highly scalable adaptive photonic beamformer using a single mode to multimode optical combiner,” IEEE Microwave and Wireless Component Letters, vol. 23, no. 10, pp. 563–565, Oct. 2013.
M. A. Nahmias, B. J. Shastri, A. N. Tait, and P. R. Prucnal, “A leaky integrate-and-fire laser neuron for ultrafast cognitive computing,” IEEE Journal of Selected Topics in Quantum Electronics, vol. 19, no. 5, pp. 1800212, Sep.-Oct. 2013.
A. N. Tait, B. J. Shastri, M. A. Nahmias, M. P. Fok, and P. R. Prucnal, “The DREAM: an integrated photonic thresholder,” IEEE/OSA Journal of Lightwave Technology, vol. 31, no. 8, pp. 1263–1272, Apr. 2013.
Y. Tian, Y.-K. Huang, S. Zhang, P. R. Prucnal, and T. Wang, “Demonstration of digital phase-sensitive boosting to extend signal reach for long-haul WDM systems using optical phase-conjugated copy," Optics Express, vol. 21, no. 4, pp. 5099–5106, Feb. 2013.
M. P. Fok, Y. Tian, D. Rosenbluth, and P. R. Prucnal, “Pulse lead/lag timing detection for adaptive feedback and control based on optical spike timing dependent plasticity,” Optics Letter, vol. 38, no. 4, pp. 419–421, Feb. 2013.
M. P. Chang, M. P. Fok, A. Hofmaier, and P. R. Prucnal, “Optical analog self-interference cancellation with electro-absorption modulators,” IEEE Microw. Wireless Compon Lett., vol. 23, no. 2, pp. 99–101, Feb. 2013.
J. Chang, M. P. Fok, J. Meister, and P. R. Prucnal, "A single source microwave photonic filter using a novel single-mode fiber to multimode fiber coupling technique", Optics Express, vol. 21, no. 5, pp. 5585–5593, Jan. 2013.
B. Wu, Z. Wang, Y. Tian, M. P. Fok, B. J. Shastri, D. R. Kanoff, and P. R. Prucnal, “Optical steganography based on amplified spontaneous emission noise,” Optics Express, vol. 21, no. 2, pp. 2065–2071, Jan. 2013.
B. J. Shastri, P. R. Prucnal, and D. V. Plant, “A 20-GSample/s (10 GHz × 2 clocks) burst-mode CDR based on injection-locking and space sampling for access networks,” IEEE Photonics Journal, vol. 4, no. 5, pp. 1783–1793, Oct. 2012; invited paper.
J. Chang, Y. Deng, M. P. Fok, J. Meister, and P. R. Prucnal, “A photonic microwave FIR filter using a spectrally sliced supercontinuum source,” Applied Optics, vol. 51, no. 19, pp. 4265–4268, Jun. 2012.
N. S. Rafidi, K. S. Kravtsov, Y. Tian, M. P. Fok, M. A. Nahmias, A. N. Tait, and P. R. Prucnal, “Power transfer function tailoring in a highly Ge-doped nonlinear interferometer-based all-optical thresholder using offset-spectral filtering,” IEEE Photonics Journal, vol. 4, no. 2, pp. 528–534, Apr. 2012.